Adding new root in the treelist during runing

Hii

I am using xtratreelist.In this i have created an unbound treelist.

I added a button in the form.Now i need the butt开发者_JAVA百科on to function such that when i click on the button it should add a new root in the treelist.how it can be done..please help me from the basic please...

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Here is the code from How to: Create Nodes in Unbound Mode in Code showing how to create a root node:

TreeListNode parentForRootNodes = null;
    TreeListNode rootNode = tl.AppendNode(
        new object[] { "Alfreds Futterkiste", "Germany, Obere Str. 57", "030-0074321" }, 
        parentForRootNodes);